An apparatus, method, and titanium-containing TRIP steel strip preparation process

Abstract

This invention discloses a device for preparing titanium-containing TRIP steel strip, comprising a continuous casting machine, a shearing and conveying device, a tunnel-type soaking furnace, a hot rolling mill, a laminar flow cooling device, and a coiler arranged in series. The continuous casting machine includes a water-cooled copper crucible and an induction coil. The outlet at the bottom of the crucible is rectangular, and a square continuous casting cylinder is connected to the outlet. A crystallizer is located at the end of the continuous casting cylinder near the outlet, and the outer wall of the crystallizer matches the inner wall of the continuous casting cylinder. The continuous casting cylinder is arranged laterally, with the outlet facing downwards. The connection end between the continuous casting cylinder and the outlet faces upwards. The end of the crystallizer near the outlet is an inclined surface, and the size and inclination angle of this inclined surface are the same as those of the outlet. This design avoids the use of the existing arc-shaped continuous casting machine, greatly reducing the overall height of the device. The solidification process of the alloy solution proceeds from bottom to top, and the solid-liquid interface is continuously fed by the alloy solution during its development, thus preventing the formation of defects such as pores and cracks in the resulting ingot.

Description

Technical Field

[0001] This invention relates to the field of TRIP steel preparation technology, and more specifically, to an apparatus, method, and titanium-containing TRIP steel strip preparation method. Background Technology

[0002] Transformation-induced plasticity (TRIP) steel is a multiphase steel. Its microstructure consists of a ferrite matrix with over 5% retained austenite and varying amounts of hard phases bainite and martensite. TRIP steel is a new type of automotive steel with high strength and good plasticity. Its high strength stems from the combined contributions of martensite, bainite, and solid solution strengthening by alloying elements; its good plasticity depends on the transformation of retained austenite to martensite during tensile testing, which delays crack propagation and increases uniform strain.

[0003] Currently, there are three main methods for producing TRIP steel: hot rolling, hot rolling followed by cold rolling and heat treatment, and thin-plate continuous casting and rolling (CSP) technology. Among these, the thin-plate continuous casting and rolling process for producing TRIP steel is currently the most popular research and practice area.

[0004] For example, Chinese patents CN201610406808.9 and CN201610402636.8 both relate to methods for producing low-carbon hot-rolled TRIP steel based on the ESP thin slab continuous casting and rolling process. Another example is the journal "Microstructure and Mechanical Properties of Cold-Rolled Heat-Treated TRIP Steel Prepared by Simulated CSP Process," which relates to the thin slab continuous casting and rolling (CSP) process.

[0005] However, existing continuous casting and rolling processes for producing TRIP steel, whether for ESP and CSP, or ISP and CSL, all require the use of an arc-shaped continuous casting machine. Firstly, given a fixed production volume, the arc-shaped continuous casting machine occupies excessive vertical space, increasing plant space requirements and investment. Secondly, during the casting process, the molten metal cools and solidifies from the outside in the mold, with the outer layer solidifying first. Insufficient liquid replenishment during internal solidification leads to defects such as porosity and cracks, resulting in plate-shaped ingots with porosity and cracks, thus affecting the quality of subsequently produced TRIP steel strips.

[0006] Therefore, providing a novel apparatus and method for preparing titanium-containing TRIP steel strips has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0007] The present invention adopts the following technical solution:

[0008] On the one hand, the present invention employs a preparation device for titanium-containing TRIP steel strip, comprising a continuous casting machine, a shearing and conveying device, a tunnel-type soaking furnace, a hot continuous rolling mill, a laminar flow cooling device, and a coiler arranged in series.

[0009] The continuous casting machine includes a vacuum furnace body and a water-cooled copper crucible and an induction coil disposed inside the vacuum furnace body, with the induction coil surrounding the water-cooled copper crucible;

[0010] The water-cooled copper crucible includes a crucible wall and a funnel-shaped crucible bottom, and both the crucible wall and the crucible bottom are surrounded by an induction coil;

[0011] The outlet at the bottom of the crucible is rectangular, and a square continuous casting cylinder is sealed and connected to the outlet at the bottom of the crucible. The end of the cylinder furthest from the outlet extends to the outside of the vacuum furnace body through a sealing device. A crystallizer is installed at the end of the continuous casting cylinder near the outlet, and the outer wall of the crystallizer matches the inner wall of the continuous casting cylinder.

[0012] A traction system is installed at the upper end of the crystallizer;

[0013] The continuous casting cylinder is arranged horizontally, and the outlet faces diagonally downwards;

[0014] The connection end between the continuous casting cylinder and the outlet faces upward at an angle, and the end of the crystallizer near the outlet is an inclined surface, the size and inclination angle of which are the same as those of the outlet.

[0015] Furthermore, a frustoconical groove is formed on the inclined surface of the crystallizer.

[0016] Furthermore, the traction system includes a traction cylinder and a drive system. The lower end of the traction cylinder is connected to the upper end face of the crystallizer, and the upper end extends to the top of the continuous casting cylinder and is connected to the drive system.

[0017] The traction cylinder includes an outer tube and an inner tube arranged coaxially. The space formed between the outer tube and the inner tube is the supply channel; the space inside the inner tube is the return channel, and one end of the return channel is connected to the cooling channel inside the crystallizer, while the other end is connected to the main coolant pipeline of the equipment.

[0018] Furthermore, the continuous casting cylinder is divided into a solidification zone and a traction zone in the horizontal direction. The solidification zone, which is near the outlet, is where the molten alloy liquid descends to this section for cooling and solidification, while the traction zone, which is far from the outlet, is the section where the solidified crystals are pulled.

[0019] The upper end of the traction zone has a guide through groove.

[0020] Furthermore, the drive system is mounted on top of the traction cylinder, and its output end slider is connected to the upper end of the traction cylinder via a transmission connection.

[0021] The drive system includes a linear drive mechanism, which is connected to the output end slider; the lower end of the output end slider is fixedly mounted with a driving element, and the upper end of the traction cylinder is fixedly mounted with a driven element.

[0022] In this process, the active element and the driven element are in contact. In the first state, the active element can drive the driven element to move together. In the second state, the active element cannot drive the driven element to move together.

[0023] Furthermore, the driven element includes a displacement box, an elastic unit, transmission gears, and a positioning element;

[0024] The lower end of the displacement box is fixedly connected to the upper end of the traction cylinder, and the elastic unit is installed inside the displacement box;

[0025] One end of the transmission tooth is connected to the elastic unit, and the other end is in contact with the transmission tooth groove of the driving element;

[0026] The positioning element can be vertically and slidably installed on the upper end face of the displacement box, and the positioning element can fix the transmission gear in the horizontal direction;

[0027] The active element includes a moving plate and a transmission tooth groove. The upper end of the moving plate is fixedly connected to the lower end of the output slider, and the transmission tooth groove is set on the lower end surface of the moving plate.

[0028] The end of the transmission tooth furthest from the elastic element is an isosceles triangle, and its shape matches the transmission tooth groove.

[0029] Furthermore, a guide hole is provided on the upper end face of the displacement box, and the size of the positioning component matches the guide hole.

[0030] Furthermore, the elastic unit includes a magnetorheological elastomer assembly and a mechanical spring. The magnetorheological elastomer is installed at the bottom of the displacement box, and one end of the mechanical spring is connected to the magnetorheological elastomer assembly, while the other end is a positioning element.

[0031] Furthermore, the shearing conveying device includes a single-roller conveying section and a double-roller conveying section arranged in sequence. The left end of the single-roller conveying section is connected to the continuous casting machine, and the right end of the double-roller conveying section is connected to the tunnel-type soaking furnace.

[0032] Among them, a mechanical pusher is installed on one side above the single roller conveyor section;

[0033] The single-roller conveyor section includes several conveyor rollers arranged horizontally at intervals, and a shearing device is disposed between two adjacent conveyor rollers.

[0034] Furthermore, the surface of the conveyor roller is fitted with a rubber sleeve.

[0035] Furthermore, the roller conveying section includes several conveying rollers arranged horizontally and at intervals, wherein the conveying rollers are a pair of rollers arranged vertically.

[0036] Among them, the spacing between the conveying pairs of rollers near the single roller conveyor section is equal to the thickness of the plate-shaped ingot, and the spacing between several conveying pairs of rollers decreases sequentially from left to right.

[0037] On the other hand, the present invention employs a method for preparing titanium-containing TRIP steel strip, using the aforementioned apparatus, and includes the following steps:

[0038] S1. Install the crystallizer in the solidification zone with its inclined surface close to the outlet; load the raw material to be melted into the water-cooled copper crucible; after evacuating the vacuum furnace, start the induction power supply and use the electromagnetic field to heat the raw material until it melts and keep it at that temperature for a period of time.

[0039] S2. Start the linear drive mechanism to drive the traction cylinder to move to the right. The traction cylinder drives the crystallizer to move to the right. The molten pool follows the crystallizer to the right and moves into the solidification zone. Under the cooling effect of the crystallizer, the inclined bottom layer of the molten pool solidifies to form solidified material, and is connected to the crystallizer through the frustum-shaped groove.

[0040] S3. The linear drive mechanism drives the traction cylinder to continue moving to the right, which in turn drives the crystallizer to continue moving to the right. During the ingot drawing process, a solid / liquid interface is continuously formed on the inclined surface of the crystallizer as the molten pool solidifies.

[0041] S4. The linear drive mechanism drives the traction cylinder to continue moving to the right, and the crystallizer continues to move to the right side of the continuous casting cylinder. The crystallizer pulls the molten pool on its left side down and solidifies, forming a plate-shaped ingot with an increasing length.

[0042] S5. The linear drive mechanism drives the traction cylinder to continue moving to the right until the crystallizer and part of the plate ingot move onto the single roller conveyor.

[0043] S6. The linear drive mechanism stops, and the shearing device is started to cut and separate the plate-shaped ingot from the crystallizer;

[0044] S7. Start the mechanical pusher to push the crystallizer away from the single roller conveyor section;

[0045] S8. Start the single-roller conveyor and the double-roller conveyor to convey the plate-shaped ingot backward. During the conveying process, the double-roller conveyor squeezes the plate-shaped ingot.

[0046] S9. The slab-shaped ingot enters the tunnel-type homogenizing furnace, which heats the slab-shaped ingot to the initial rolling temperature.

[0047] S10. The plate-shaped ingot enters the hot strip mill, which rolls the plate-shaped ingot into steel strip.

[0048] S11. The steel strip passes through a laminar flow cooling device and is then coiled by a coiler for storage.

[0049] Furthermore, steps 3 and / or 4 include:

[0050] S31. When the resistance between the side wall of the solidified material of the drawn billet and the inner wall of the solidification zone does not reach the critical value, the output end slider moves to the right, the active element can drive the driven element to move together, and the linear drive mechanism drives the traction cylinder to continue to move to the right.

[0051] S32. When the resistance between the side wall of the solidified material of the drawn billet and the inner wall of the solidification zone reaches the critical value, the output end slider moves to the right. The active element cannot drive the driven element to move together, the crystallizer automatically stops moving to the right, and feeds the signal back to the control system.

[0052] S33. The control system sends a control signal to the magnetorheological elastomer assembly to increase the elastic coefficient of the elastic unit. The linear drive mechanism drives the crystallizer to move rapidly left and right with a small amplitude for a certain period of time. This reduces the resistance between the solidified material and the inner wall of the solidification zone through mutual friction.

[0053] S34. The control system sends a control signal to the magnetorheological elastomer assembly to restore the elastic coefficient of the elastic unit. The linear drive mechanism drives the output end slider to continue moving to the right. The active element can drive the driven element to move together. The linear drive mechanism drives the traction cylinder to continue moving to the right until the ingot traction process is completed.

[0054] Furthermore, the present invention provides a titanium-containing TRIP steel strip, prepared using the above-described method, containing the following components based on the total mass:

[0055] 0.18–0.38% wt% C, 0.7–1.1% wt% Si, 1.8–2.3% wt% Mn, 0.98–1.33% wt% Al, 0.05–0.09% wt% V, 0.1–0.2% wt% Ti, 0–0.005% wt% N, with the balance being Fe and unavoidable impurities.

[0056] Compared with the prior art, the present invention has the following advantages:

[0057] The continuous casting cylinder is arranged horizontally, and the continuously produced plate-shaped ingots are directly arranged and move horizontally, avoiding the use of the existing arc-shaped continuous casting machine, greatly reducing the overall height of the equipment and facilitating the layout of the plant.

[0058] Through the unique shape configuration of the water-cooled copper crucible, continuous casting cylinder, and crystallizer, the solidification process of the alloy solution during the ingot drawing process proceeds from bottom to top. The solid-liquid interface is continuously fed by the alloy solution during the development process, so no defects such as pores and cracks are formed in the resulting ingot.

[0059] When the end of the plate-shaped ingot moves above the single-roller conveyor via the shearing conveyor, the shearing device cuts the plate-shaped ingot, separating it from the crystallizer. After separation, the mechanical pusher grabs the crystallizer away from the single-roller conveyor, while the single-roller conveyor continues to convey the plate-shaped ingot backward.

[0060] The roller conveyor not only performs the function of conveying, but also applies pressure to the plate-shaped ingot, improving the microstructure and mechanical properties of the plate-shaped ingot.

[0061] When the resistance between the side wall of the drawn billet and the inner wall of the solidification zone is too great, the driving element cannot move with the driven element, automatically preventing the resistance between the side wall of the billet and the inner wall of the solidification zone from becoming too great. This is not achieved by relying solely on sensor measurement signals to control the drive system to stop moving.

[0062] By using an actively controlled elastic unit, when the drive system drives the traction cylinder to move rapidly left and right with small amplitudes, the elastic coefficient of the elastic unit is increased, preventing the transmission teeth from disengaging from the transmission tooth groove, thus ensuring the micro-vibration of the crystallizer. During the ingot drawing process, the elastic coefficient of the elastic unit is decreased, allowing the transmission teeth to disengage from the transmission tooth groove in the second state.

[0063] By adding the microalloying element titanium, a dispersed second phase is formed in the steel, which can refine the grains, improve the stability of the retained austenite, and improve the performance of TRIP steel. Attached Figure Description

[0064] Figure 1 Diagram of the device;

[0065] Figure 2 Structure of a continuous casting machine Figure 1 ;

[0066] Figure 3 for Figure 2 Enlarged view of a portion of point A in the middle;

[0067] Figure 4 Structure of a continuous casting machine Figure 2 ;

[0068] Figure 5 This is a sectional view of a continuous casting machine.

[0069] Figure 6 for Figure 5 Enlarged view of a section at point B in the middle;

[0070] Figure 7 for Figure 5 Enlarged view of a section at point C;

[0071] Figure 8 Here is a diagram of the crystallizer structure;

[0072] Figure 9 For illustrative purposes only Figure 1 ;

[0073] Figure 10 For illustrative purposes only Figure 2 ;

[0074] Figure 11 For illustrative purposes only Figure 3 ;

[0075] Figure 12 For illustrative purposes only Figure 4 . Detailed Implementation

[0076] The following detailed description of embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0077] like Figure 1-12 As shown, this embodiment provides an apparatus for preparing titanium-containing TRIP steel strip, including a continuous casting machine 100, a shearing and conveying device 200, a tunnel-type soaking furnace 300, a hot rolling mill 400, a laminar flow cooling device 500, and a coiler 600 arranged in series.

[0078] The continuous casting machine 100 is used to melt the raw materials and form continuously produced plate-shaped ingots 700. The shearing and conveying device 200 is used to transport the plate-shaped ingots 700 to the tunnel-type soaking furnace 300. The tunnel-type soaking furnace 300 is used to heat the plate-shaped ingots 700. The hot continuous rolling mill 400 is used to roll the plate-shaped ingots 700 into steel strips 800. The laminar flow cooling device 500 and the coiler 600 are used to cool and coil the steel strips 800 for storage.

[0079] Generally, a high-pressure water descaling device is installed before the tunnel-type soaking furnace 300 to remove iron oxide scale and protective slag residue from the upper and lower surfaces of the plate-shaped ingot 700; a high-pressure water descaling device is also installed between the tunnel-type soaking furnace 300 and the hot continuous rolling mill 400 to perform a final removal of iron oxide scale from the upper and lower surfaces of the plate-shaped ingot 700; a flying shear is also installed before the coiler 600 to cut the steel strip 800 after the coiler 600 has finished coiling one coil. As prior art, this embodiment does not impose specific limitations on these aspects.

[0080] In this embodiment, a plate-shaped ingot 700 containing titanium TRIP steel strip is prepared using vacuum suspension melting technology to eliminate the problem of impurities introduced in traditional casting methods, as well as defects such as porosity and cracks inside and on the surface of the ingot in traditional casting methods.

[0081] Specifically, the continuous casting machine 100 includes a vacuum furnace body 3 and a water-cooled copper crucible 1 and an induction coil 2 disposed within the vacuum furnace body 3, with the induction coil 2 surrounding the water-cooled copper crucible 1.

[0082] As a current technology, a suspension melting system generally includes a vacuum unit, an induction power supply, a cooling system, and a control system. After the vacuum unit evacuates the vacuum furnace body 3, the high-frequency current generated by the induction power supply is input into the induction coil 2. The high-frequency electromagnetic field generated by the induction coil 2 heats and melts the material in the water-cooled copper crucible 1. The cooling system supplies cooling water to the water-cooled copper crucible 1, the induction coil 2, the induction power supply, the vacuum furnace body 3, and the vacuum unit to protect these devices.

[0083] It is understood that the water-cooled copper crucible 1 includes a cylindrical crucible wall 11 and a crucible bottom 12; and, in order to allow electromagnetic field energy to penetrate the crucible wall and enter the interior of the water-cooled copper crucible 1, the water-cooled copper crucible 1 is mostly processed into several segmented structures, with gaps formed between the segments so that electromagnetic field energy can penetrate the crucible wall.

[0084] It should be noted that in this embodiment, the crucible bottom 12 of the water-cooled copper crucible 1 is funnel-shaped, and both the crucible wall 11 and the crucible bottom 12 are surrounded by an induction coil 2.

[0085] Therefore, in this embodiment, the water-cooled copper crucible 1 is surrounded by an induction coil 2. The titanium-containing TRIP steel raw material is melted in the water-cooled copper crucible 1 to form a molten pool. That is, the water-cooled copper crucible 1 is a smelting zone as a whole.

[0086] It is understood that the shape of the crucible wall 11 can be cylindrical or rectangular, and this embodiment does not specifically limit it. The shape of the crucible bottom 12 matches the crucible wall 11. It should be noted that the outlet 13 of the crucible bottom 12 must be rectangular in order to continuously produce plate-shaped ingots 700.

[0087] In this embodiment, a square continuous casting cylinder 14 is sealed and connected to the outlet 13 of the crucible bottom 12, and one end of the cylinder away from the outlet 13 extends to the outside of the vacuum furnace body 3 through a sealing device. A crystallizer 15 is provided inside the continuous casting cylinder 14 near the outlet 13. The crystallizer 15 is a device that carries the molten pool during the melting process and causes the bottom of the molten pool to solidify on its surface.

[0088] Specifically, the outer wall of the crystallizer 15 matches the inner wall of the continuous casting cylinder 14. In the initial position, the continuous casting cylinder 14 is positioned at its end to seal the outlet 13 of the water-cooled copper crucible 1. It can be understood that this matching means that the crystallizer 15 can move within the continuous casting cylinder 14 and prevent leakage of the molten alloy.

[0089] The continuous casting cylinder 14 is arranged horizontally. The outlet 13 faces downwards. Correspondingly, the connection end between the continuous casting cylinder 14 and the outlet 13 faces upwards, and the end of the crystallizer 15 near the outlet 13 is an inclined surface 151, the size and inclination angle of which are the same as those of the outlet 13.

[0090] With the above settings, on the one hand, the continuous casting cylinder 14 is arranged horizontally, and the continuously produced plate-shaped ingots 700 are directly arranged and move horizontally, avoiding the use of the existing arc-shaped continuous casting machine, greatly reducing the overall height of the device, which is beneficial to the layout of the plant.

[0091] On the other hand, the outlet 13 faces downwards, the connection end of the continuous casting cylinder 14 and the outlet 13 faces upwards, and the end of the crystallizer 15 near the outlet 13 is an inclined surface 151. Through the unique shape configuration of the cold copper crucible 1, the continuous casting cylinder 14 and the crystallizer 15, the solidification process of the alloy solution during the ingot drawing process is from bottom to top, and the solid-liquid interface is constantly replenished by the alloy solution during the development process. Therefore, no defects such as pores and cracks will be formed in the ingot.

[0092] In this embodiment, a frustum-shaped groove 152 is provided on the inclined surface 151 of the crystallizer 15, so that the alloy liquid combines with the crystallizer 15 after solidifying inside the frustum-shaped groove 152, so that the crystallizer 15 can pull the ingot solidified on the inclined surface 151.

[0093] In this embodiment, a cooling channel 153 is provided inside the crystallizer 15, so that the crystallizer 15 can cool the molten pool and ingot on the inclined surface 151, and prevent the crystallizer 15 from being damaged by the high temperature of the molten pool.

[0094] In this embodiment, a traction system 5 is installed at the upper end of the crystallizer 15 so that the crystallizer 15 can move left and right within the continuous casting cylinder 14.

[0095] Specifically, the traction system 5 includes a traction cylinder 51 and a drive system 52. The lower end of the traction cylinder 51 is connected to the upper end face of the crystallizer 15, and the upper end extends to the top of the continuous casting cylinder 14 and is connected to the drive system 52.

[0096] The traction cylinder 51 includes an outer tube 511 and an inner tube 512 arranged coaxially. The space formed between the outer tube 511 and the inner tube 512 is a supply channel 513 for supplying coolant to the cooling channel 153 inside the crystallizer 15. The space inside the inner tube 512 is a return channel 514. One end of the return channel 514 is connected to the cooling channel 153 inside the crystallizer 15, and the other end is connected to the main coolant pipeline of the equipment.

[0097] Therefore, in this embodiment, the continuous casting cylinder 14 is divided into two working zones in the horizontal direction. The working zone near the outlet 13 is where the molten alloy liquid descends to this section for cooling and solidification, while the working zone away from the outlet 13 is where the solidified crystals are drawn. These are respectively referred to as the solidification zone 141 and the drawing zone 142 of the continuous casting cylinder 14.

[0098] Understandably, in the initial position, the solidification zone 141 is sealed by the inclined surface 151 of the crystallizer 15 to form a sealed space. During the ingot drawing process, the solidification zone 141 is always sealed by the already solidified crystal. During the ingot drawing process, the solid-liquid interface remains in an inclined state throughout its development, and the alloy solution is continuously replenished from top to bottom. Therefore, the solid-liquid interface is constantly fed by the alloy solution during its development, so no defects such as pores or cracks are formed in the resulting ingot.

[0099] It is understandable that the upper end of the traction zone 142 is provided with a guide through groove 143 to facilitate the lateral movement of the traction cylinder 51.

[0100] In this embodiment, the drive system 52 is mounted on top of the traction cylinder 51, and its output end slider 53 is connected to the upper end of the traction cylinder 51 via a transmission connection; the drive system 52 can drive the traction cylinder 51 to move in one direction left and right, and can also drive the traction cylinder 51 to move quickly with a small amplitude left and right.

[0101] Understandably, the drive system 52 drives the traction cylinder 51 to move in one direction to the right, with the purpose of pulling the ingot to the right to form a plate-shaped ingot 700; the drive system 52 drives the traction cylinder 51 to move in one direction to the left, with the purpose of restoring the crystallizer 15 to its original position after one process.

[0102] It is worth mentioning that the drive system 52 drives the traction cylinder 51 to move left and right in a small and rapid manner. The purpose is to prevent the molten pool from sticking together when it solidifies in the solidification zone 141, and to promote the smooth movement of the solidified ingot to the right.

[0103] The working principle of the pull-down ingot in this embodiment is as follows:

[0104] First, the crystallizer 15 is installed in the solidification zone 141, with its inclined surface 151 close to the outlet 13; the raw material to be melted is loaded into the water-cooled copper crucible 1, and after the vacuum furnace body 3 is evacuated, the induction power supply is started, and the raw material is heated to melt by electromagnetic field and kept at the temperature for a period of time.

[0105] Then, the drive system 52 is started to drive the traction cylinder 51 to move to the right. The traction cylinder 51 drives the crystallizer 15 to move to the right. The molten pool follows the crystallizer 15 to move to the right into the solidification zone 141. Under the cooling effect of the crystallizer 15, the inclined bottom layer of the molten pool solidifies to form solidified material, and is connected to the crystallizer 15 through the frustum-shaped groove 152. During the ingot drawing process, a solid / liquid interface is formed when the molten pool solidifies on the inclined surface 151 of the crystallizer 15.

[0106] Finally, the crystallizer 15 continues to move to the right, pulling the molten pool on its left side downwards and solidifying, forming an ingot of increasing length. Because the molten pool moves downwards, the solid-liquid interface is continuously fed by the alloy solution during the development process, so no defects such as pores or cracks are formed in the resulting ingot.

[0107] Understandably, in order to enable the ingot drawing process to proceed continuously and obtain a long plate-shaped ingot 700, this embodiment provides a continuous feeding device at the top of the vacuum furnace body 3 to achieve continuous ingot drawing.

[0108] During the ingot drawing process, the sidewall of the ingot pulled to the right moves along the inner wall of the solidification zone 141, generating resistance between them. If the resistance is too great, forcibly continuing to draw the ingot will cause significant stress in the ingot, leading to cracks and damaging the surface quality of the ingot. In view of this, in this embodiment, the drive system 52 can drive the traction cylinder 51 to move rapidly left and right with small amplitudes.

[0109] Understandably, the drive system 52 drives the traction cylinder 51 to move left and right rapidly with small amplitudes. The purpose is to break the adhesion between the solidified material and the solidified zone 141 when the molten pool solidifies and causes excessive resistance due to adhesion.

[0110] In this embodiment, the drive system 52 includes a linear drive mechanism 54, which is connected to the output end slider 53; the lower end of the output end slider 53 is fixedly mounted with an active element 55, and the upper end of the traction cylinder 51 is fixedly mounted with a driven element 56.

[0111] In this configuration, the active element 55 is in contact with the driven element 56. In the first state, the active element 55 can drive the driven element 56 to move together. In the second state, the active element 55 cannot drive the driven element 56 to move together.

[0112] Understandably, when the drive system 52 drives the traction cylinder 51 and the crystallizer 15 to move to the left to return to their original positions, and when the drive system 52 drives the traction cylinder 51 to move rapidly to the left and right with small amplitudes, the active element 55 can drive the driven element 56 to move together. During the process of the drive system 52 driving the traction cylinder 51 to move to the right to draw the billet, under normal conditions, the active element 55 can drive the driven element 56 to move together; when the resistance between the side wall of the drawn billet and the inner wall of the solidification zone 141 is too large, the active element 55 cannot drive the driven element 56 to move together.

[0113] Therefore, the first state refers to the normal state when the drive system 52 drives the traction cylinder 51 to move to the left to return to its original position, when the drive system 52 drives the traction cylinder 51 to move rapidly to the left and right with a small amplitude, and when the drive system 52 drives the traction cylinder 51 to move to the right to guide the ingot. The second state refers to the state when the resistance between the ingot and the solidification zone 141 is too large during the process of the drive system 52 driving the traction cylinder 51 to move to the right to guide the ingot.

[0114] Therefore, during the ingot drawing process, in the first state, the active element 55 can drive the driven element 56 to move together to draw the ingot to the right; when the resistance between the side wall of the drawn ingot and the inner wall of the solidification zone 141 is too large and reaches the critical value, that is, in the second state, the active element 55 cannot drive the driven element 56 to move together. At this time, although the active element 55 still moves, the driven element 56 no longer moves to the right, automatically preventing the resistance between the side wall of the ingot and the inner wall of the solidification zone 141 from being too large.

[0115] It is understood that the linear drive mechanism 54 can be an electric actuator, a hydraulic rod, or a lead screw and nut mechanism, and this embodiment does not limit this. This embodiment preferably uses a lead screw and nut mechanism. Obviously, the power source for driving the lead screw to rotate is a forward and reverse motor so that the traction cylinder 51 can move left and right.

[0116] In this embodiment, the driven element 56 includes a displacement box 561, an elastic unit 562, a transmission gear 563, and a positioning member 564. The lower end of the displacement box 561 is fixedly connected to the upper end of the traction cylinder 51, and the elastic unit 562 is installed inside the displacement box 561. The transmission gear 563 contacts the elastic unit 562 and the driving element 55, thus, the transmission gear 563 is the component that connects the driving element 55 and the driven element 56. Specifically, the transmission gear 563 is vertically movable and disposed in the displacement box 561. One end of the transmission gear 563 is connected to the elastic unit 562, and the other end contacts the transmission tooth groove 551 of the driving element 55. The positioning member 564 is vertically slidably mounted on the upper end surface of the displacement box 561. The positioning member 564 can fix the transmission gear 563 in the horizontal direction, so that the transmission gear 563 cannot move horizontally relative to the displacement box 561.

[0117] Specifically, the upper end face of the displacement box 561 is provided with a guide through hole 565, and the size of the positioning member 564 matches the guide through hole 565 so that the positioning member 564 can slide vertically in the guide through hole 565 so that the transmission gear 563 can be elastically retracted into the displacement box 561.

[0118] The active element 55 includes a movable plate 552 and a transmission tooth groove 551. The upper end of the movable plate 552 is fixedly connected to the lower end of the output slider 53. The side of the movable plate 552 opposite to the displacement box 561 is a transmission structure. The transmission tooth groove 551 is provided on the lower end surface of the movable plate 552. The end of the transmission tooth 563 away from the elastic unit 562 is an isosceles triangle, and its shape matches the transmission tooth groove 55.

[0119] Therefore, in the first state, the transmission tooth 563 is in the state of extending out of the displacement box 561 under the action of the elastic unit 562. The transmission tooth 563 always maintains a meshing state with the transmission tooth groove 551, and the moving plate 552 can drive the displacement box 561 to move together. In the second state, the transmission tooth 563 and the transmission tooth groove 551 are pressed against each other, and the pressing force between the two is greater than the elastic force of the elastic unit 562. The transmission tooth 563 compresses the elastic unit 562 to produce elastic deformation. The transmission tooth 563 continuously enters the next adjacent transmission tooth groove 551 from one transmission tooth groove 551. The moving plate 552 cannot drive the displacement box 561 to move together.

[0120] Thus, the automatic stop function of the drive system 52 is realized, instead of relying solely on sensor measurement signals to control the drive system 52 to stop moving, avoiding excessive resistance between the billet and the solidification zone 141 caused by control signal feedback lag.

[0121] In this embodiment, the elastic unit 562 is an actively controlled spring, so that during the ingot drawing process, the elasticity of the elastic unit 562 can be adjusted according to the set critical resistance value between the side wall of the billet and the inner wall of the solidification zone 141. More importantly, when the drive system 52 drives the traction cylinder 51 to move left and right rapidly with small amplitudes, the elastic force of the elastic unit 562 is increased to ensure the micro-vibration of the crystallizer 15.

[0122] Specifically, the elastic unit 562 includes a magnetorheological elastomer assembly 57 and a mechanical spring 58. The magnetorheological elastomer 57 is installed at the bottom of the displacement box 561, and one end of the mechanical spring 58 is connected to the magnetorheological elastomer assembly 57, while the other end is connected to the positioning member 564.

[0123] With the above settings, when the drive system 52 drives the traction cylinder 51 to move rapidly left and right with small amplitudes, the elastic coefficient of the elastic unit 562 is increased, preventing the transmission tooth 563 from disengaging from the transmission tooth groove 551. During the spindle drawing process, the elastic coefficient of the elastic unit 562 is decreased, allowing the transmission tooth 563 to disengage from the transmission tooth groove 551 in the second state.

[0124] Understandably, the magnetorheological elastomer assembly 57 can employ existing mature technologies. Furthermore, the magnetorheological elastomer assembly 57 is electrically connected to the control system.

[0125] In this embodiment, the shearing conveyor 200 includes a single-roller conveyor section 210 and a double-roller conveyor section 220 arranged sequentially. The left end of the single-roller conveyor section 210 receives the continuous casting machine 100, and the right end of the double-roller conveyor section 220 receives the tunnel-type soaking furnace 300. A shearing device 230 is disposed below the single-roller conveyor section 210, and a mechanical pusher 240 is disposed on one side above the single-roller conveyor section 210.

[0126] Specifically, the single-roller conveyor section 210 includes a plurality of conveyor rollers 211 arranged horizontally and at intervals. A shearing device 230 is disposed between two adjacent conveyor rollers 211 so that when the end of the plate-shaped ingot 700 moves above the single-roller conveyor section 210, the shearing device 230 cuts the plate-shaped ingot 700, separating the plate-shaped ingot 700 from the crystallizer 15. After the crystallizer 15 is separated, the mechanical pusher 240 grabs the crystallizer 15 away from the single-roller conveyor section 210, and the single-roller conveyor section 210 continues to convey the plate-shaped ingot 700 backward.

[0127] Preferably, in this embodiment, the number of conveying rollers 211 is four, and the shearing device 230 is disposed between the second and third conveying rollers 211. Preferably, the surface of the conveying rollers 211 is provided with rubber sleeves to improve the conveying performance of the single-roller conveying section 210.

[0128] Specifically, the roller conveying unit 220 includes a plurality of conveying rollers 221 arranged horizontally and at intervals, wherein the conveying rollers 221 are a pair of rollers arranged vertically.

[0129] In this configuration, the spacing between the conveying rollers 221 near the single-roller conveyor section 210 is equal to the thickness of the plate-shaped ingot 700, and the spacing between the several conveying rollers 221 decreases sequentially from left to right. Thus, the roller conveyor section 220 not only performs the function of conveying but also applies pressure to the plate-shaped ingot 700, improving its microstructure and mechanical properties.

[0130] This embodiment also provides a method for preparing titanium-containing TRIP steel strip, comprising the following steps:

[0131] S1. Install the crystallizer 15 in the solidification zone 141 and make its inclined surface 151 close to the outlet 13; put the raw material to be melted into the water-cooled copper crucible 1, and after evacuating the vacuum furnace body 3, start the induction power supply and use the electromagnetic field to heat the raw material until it melts and keep it at a certain temperature for a period of time.

[0132] S2. Start the linear drive mechanism 54 to drive the traction cylinder 51 to move to the right. The traction cylinder 51 drives the crystallizer 15 to move to the right. The molten pool follows the crystallizer 15 to move to the right into the solidification zone 141. Under the cooling effect of the crystallizer 15, the inclined bottom layer of the molten pool solidifies to form solidified material, and is connected to the crystallizer 15 through the frustum-shaped groove 152.

[0133] S3. The linear drive mechanism 54 drives the traction cylinder 51 to continue moving to the right, which in turn drives the crystallizer 15 to continue moving to the right. During the ingot drawing process, a solid / liquid interface is continuously formed on the inclined surface 151 of the crystallizer 15 when the molten pool solidifies.

[0134] S4. The linear drive mechanism 54 drives the traction cylinder 51 to continue moving to the right, and the crystallizer 15 continues to move to the right side of the continuous casting cylinder 14. The crystallizer 15 pulls the molten pool on its left side down and solidifies, forming a plate-shaped ingot 700 with an increasing length.

[0135] S5, the linear drive mechanism 54 drives the traction cylinder 51 to continue moving to the right until the crystallizer 15 and part of the plate ingot 700 move onto the single roller conveyor 210.

[0136] S6. The linear drive mechanism 54 stops, and the shearing device 230 is started to cut and separate the plate-shaped ingot 700 from the crystallizer 15.

[0137] S7. Start the mechanical pusher 24 to push the crystallizer 15 away from the single roller conveyor section 210;

[0138] S8. Start the single roller conveyor 210 and the double roller conveyor 220 to convey the plate-shaped ingot 700 backward. During the conveying process, the double roller conveyor 220 squeezes the plate-shaped ingot 700.

[0139] S9. The plate-shaped ingot 700 enters the tunnel-type homogenizing furnace 300, which heats the plate-shaped ingot 700 to the initial rolling temperature.

[0140] S10, the plate-shaped ingot 700 enters the hot strip mill 400, and the hot strip mill 400 rolls the plate-shaped ingot 700 into steel strip 800.

[0141] S11, the steel strip 800 passes through the laminar flow cooling device 500 and is then coiled by the coiler 600 for storage.

[0142] Step 3 and / or step 4 include:

[0143] S31. When the resistance between the side wall of the solidified material of the drawn billet and the inner wall of the solidification zone 141 does not reach the critical value, the output end slider 53 moves to the right, the active element 55 can drive the driven element 56 to move together, and the linear drive mechanism 54 drives the traction cylinder 51 to continue to move to the right.

[0144] S32. When the resistance between the side wall of the solidified material of the drawn billet and the inner wall of the solidification zone 141 reaches the critical value, the output end slider 53 moves to the right, the active element 55 cannot drive the driven element 56 to move together, the crystallizer 15 automatically stops moving to the right, and feeds the signal back to the control system.

[0145] S33, the control system sends a control signal to the magnetorheological elastomer assembly 57 to increase the elastic coefficient of the elastic unit 562, and the linear drive mechanism 54 drives the crystallizer 15 to move rapidly and slightly for a certain period of time; thereby reducing the resistance between the solidified material 100 and the solidification zone 141 through mutual friction between the side wall and the inner wall.

[0146] S34. The control system sends a control signal to the magnetorheological elastomer assembly 57 to restore the elastic coefficient of the elastic unit 562. The linear drive mechanism 54 drives the output end slider 53 to continue moving to the right. The active element 55 can drive the driven element 56 to move together. The linear drive mechanism 54 drives the traction cylinder 51 to continue moving to the right until the ingot drawing process is completed.

[0147] This embodiment also provides a titanium-containing TRIP steel strip, which, based on total mass, contains the following components: 0.18–0.38% wt% C, 0.7–1.1% wt% Si, 1.8–2.3% wt% Mn, 0.98–1.33% wt% Al, 0.05–0.09% wt% V, 0.1–0.2% wt% Ti, 0–0.005% wt% N, with the balance being Fe and unavoidable impurities.

[0148] By adding the microalloying element titanium, a dispersed second phase is formed in the steel, which can refine the grains, improve the stability of the retained austenite, and improve the performance of TRIP steel.

[0149] The above description provides examples of the preferred embodiments of the present invention. Parts not detailed herein are common knowledge to those skilled in the art. The scope of protection of the present invention is determined by the claims. Any equivalent modifications based on the technical teachings of the present invention are also within the scope of protection of the present invention.

Claims

1. An apparatus for preparing titanium-containing TRIP steel strip, comprising a continuous casting machine, a shearing and conveying device, a tunnel-type soaking furnace, a hot continuous rolling mill, a laminar flow cooling device, and a coiler arranged in series. Its features are, The continuous casting machine includes a vacuum furnace body and a water-cooled copper crucible and an induction coil disposed inside the vacuum furnace body, with the induction coil surrounding the water-cooled copper crucible; The water-cooled copper crucible includes a crucible wall and a funnel-shaped crucible bottom, and both the crucible wall and the crucible bottom are surrounded by an induction coil; The outlet at the bottom of the crucible is rectangular, and a square continuous casting cylinder is sealed and connected to the outlet at the bottom of the crucible. The end of the cylinder furthest from the outlet extends to the outside of the vacuum furnace body through a sealing device. A crystallizer is installed at the end of the continuous casting cylinder near the outlet, and the outer wall of the crystallizer matches the inner wall of the continuous casting cylinder. A traction system is installed at the upper end of the crystallizer; The continuous casting cylinder is arranged horizontally, and the outlet faces diagonally downwards; The connection end between the continuous casting cylinder and the outlet faces upward at an angle, and the end of the crystallizer near the outlet is an inclined surface, and the size and inclination angle of this inclined surface are the same as those of the outlet. The traction system includes a traction cylinder and a drive system. The lower end of the traction cylinder is connected to the upper end face of the crystallizer, and the upper end extends to the top of the continuous casting cylinder and is connected to the drive system. The drive system is mounted on top of the traction drum, and its output end slider is connected to the upper end of the traction drum via a transmission connection. The drive system includes a linear drive mechanism, which is connected to the output end slider; the lower end of the output end slider is fixedly mounted with a driving element, and the upper end of the traction cylinder is fixedly mounted with a driven element. Among them, when the active element and the driven element are in contact, the active element can drive the driven element to move together when the drive system drives the traction cylinder to move to the left to return to its original position, when the drive system drives the traction cylinder to move rapidly to the left and right with a small amplitude, and when the drive system drives the traction cylinder to move to the right to draw the ingot during the normal state. When the resistance between the billet and the solidification zone is too large during the process of the drive system driving the traction cylinder to move to the right to draw the ingot, the active element cannot drive the driven element to move together. Driven elements include displacement boxes, elastic units, transmission gears, and positioning components; The lower end of the displacement box is fixedly connected to the upper end of the traction cylinder, and the elastic unit is installed inside the displacement box; One end of the transmission tooth is connected to the elastic unit, and the other end is in contact with the transmission tooth groove of the driving element; The positioning element can be vertically slidably installed on the upper end face of the displacement box, and the positioning element can fix the transmission gear in the horizontal direction; The active element includes a moving plate and a transmission tooth groove. The upper end of the moving plate is fixedly connected to the lower end of the output slider, and the transmission tooth groove is set on the lower end surface of the moving plate. The end of the transmission tooth furthest from the elastic element is an isosceles triangle, and its shape matches the transmission tooth groove.

2. The apparatus as described in claim 1, characterized in that: A frustoconical groove is provided on the inclined surface of the crystallizer.

3. The apparatus as described in claim 1, characterized in that: The traction cylinder includes an outer tube and an inner tube arranged coaxially. The space formed between the outer tube and the inner tube is the supply channel; the space inside the inner tube is the return channel, and one end of the return channel is connected to the cooling channel inside the crystallizer, and the other end is connected to the main coolant pipeline of the equipment.

4. The apparatus as described in claim 3, characterized in that: The continuous casting cylinder is divided into a solidification zone and a traction zone in the horizontal direction. The solidification zone, which is near the outlet, is where the molten alloy liquid descends to cool and solidify. The traction zone, which is far from the outlet, is where the solidified crystals are pulled. The upper end of the traction zone has a guide through groove.

5. The apparatus according to any one of claims 1-4, characterized in that: The shearing conveyor includes a single-roller conveyor section and a double-roller conveyor section arranged in sequence. The left end of the single-roller conveyor section is connected to the continuous casting machine, and the right end of the double-roller conveyor section is connected to the tunnel-type soaking furnace. Among them, a mechanical pusher is installed on one side above the single roller conveyor section; The single-roller conveyor section includes several conveyor rollers arranged horizontally at intervals, and a shearing device is disposed between two adjacent conveyor rollers.

6. A method for preparing titanium-containing TRIP steel strip, using the apparatus described in any one of claims 1-5, characterized in that, Includes the following steps: S1. Install the crystallizer in the solidification zone with its inclined surface close to the outlet; load the raw material to be melted into the water-cooled copper crucible; after evacuating the vacuum furnace, start the induction power supply and use the electromagnetic field to heat the raw material until it melts and keep it at that temperature for a period of time. S2. Start the linear drive mechanism to drive the traction cylinder to move to the right. The traction cylinder drives the crystallizer to move to the right. The molten pool follows the crystallizer to the right and moves into the solidification zone. Under the cooling effect of the crystallizer, the inclined bottom layer of the molten pool solidifies to form solidified material, and is connected to the crystallizer through the frustum-shaped groove. S3. The linear drive mechanism drives the traction cylinder to continue moving to the right, which in turn drives the crystallizer to continue moving to the right. During the ingot drawing process, a solid / liquid interface is continuously formed on the inclined surface of the crystallizer as the molten pool solidifies. S4. The linear drive mechanism drives the traction cylinder to continue moving to the right, and the crystallizer continues to move to the right side of the continuous casting cylinder. The crystallizer pulls the molten pool on its left side down and solidifies, forming a plate-shaped ingot with an increasing length. S5. The linear drive mechanism drives the traction cylinder to continue moving to the right until the crystallizer and part of the plate ingot move onto the single roller conveyor. S6. The linear drive mechanism stops, and the shearing device is started to cut and separate the plate-shaped ingot from the crystallizer; S7. Start the mechanical pusher to push the crystallizer away from the single roller conveyor section; S8. Start the single-roller conveyor and the double-roller conveyor to convey the plate-shaped ingot backward. During the conveying process, the double-roller conveyor squeezes the plate-shaped ingot. S9. The slab-shaped ingot enters the tunnel-type homogenizing furnace, which heats the slab-shaped ingot to the initial rolling temperature. S10. The plate-shaped ingot enters the hot strip mill, which rolls the plate-shaped ingot into steel strip. S11. The steel strip passes through a laminar flow cooling device and is then coiled by a coiler for storage. Step 3 and / or step 4 include: S31. When the resistance between the side wall of the solidified material of the drawn billet and the inner wall of the solidification zone does not reach the critical value, the output end slider moves to the right, the active element can drive the driven element to move together, and the linear drive mechanism drives the traction cylinder to continue to move to the right. S32. When the resistance between the side wall of the solidified material of the drawn billet and the inner wall of the solidification zone reaches the critical value, the output end slider moves to the right. The active element cannot drive the driven element to move together, the crystallizer automatically stops moving to the right, and feeds the signal back to the control system. S33. The control system sends a control signal to the magnetorheological elastomer assembly to increase the elastic coefficient of the elastic unit. The linear drive mechanism drives the crystallizer to move rapidly left and right with a small amplitude for a certain period of time. This reduces the resistance between the solidified material and the inner wall of the solidification zone through mutual friction. S34. The control system sends a control signal to the magnetorheological elastomer assembly to restore the elastic coefficient of the elastic unit. The linear drive mechanism drives the output end slider to continue moving to the right. The active element can drive the driven element to move together. The linear drive mechanism drives the traction cylinder to continue moving to the right until the ingot traction process is completed.

Images